212 Mayow 



minutes only, will die immediately after its breath is 

 stopped, this is not because the movement of the 

 blood is prevented ; for the blood could be carried 

 round by the foramen ovale and the ductus arteriosus^ 

 since these passages, to which it is accustomed, are 

 not yet closed. 



It is therefore to be absolutely concluded that the 

 necessity for breathing arises from this, that certain 

 nitro-aerial particles requisite for the support of life 

 are transmitted by means of the lungs into the blood, 

 as I consider to be established by what is stated 

 elsewhere. And therefore inasmuch as the foetus 

 cannot breathe in the womb, as the air is excluded, it 

 is necessary that the lack of respiration should be 

 supplied from another source. 



For we cannot agree with those who maintain that 

 the foetus breathes even in the womb — a view upheld 

 on the strength of the vagitus uterinus and the suctio 

 infantuli. But indeed it seems to me that air can 

 just as well pass to the blood, without respiration, 

 through the skin and veins, as penetrate the closed 

 uterus and the many membranes which enfold the 

 foetus. Although I would not deny that vapours 

 arising from the fermentation of juices are perhaps 

 sometimes contained in the amnion ; and these may 

 produce the vagitus uterinus and the suctio^ but they 

 cannot serve the purpose of respiration, since they 

 would need to be driven out oftener from the lungs of 

 the embryo. Indeed, for the suctio infantuli^ there is 

 no need at all that air or vapours should be contained 

 in the amnion, for the external air, by compressing 

 and pushing not only the outer parts of the body, but, 

 by their intervention, all the internal parts also, and, 

 consequently, the liquids of the amnion, is able to 

 cause suction in the uterus. 



